Note that most of these tests are somewhat brittle. Their outcome depends on the data for the API, the API server and the functionality of the API tools. A failing test my indicate an error in each of these layers. Or even an unpredicted probabilistic occurrence like no artist with "fo" in the name playing right now. In case of failure take a good look at the test setup and whether the tests my depend on probability or not. In doubt run the test again some time later.